


Fall 2015 Smutmas Collection

by PineWreaths



Series: Smutmas [1]
Category: Gravity Falls
Genre: Bondage, Drabble, Exhibitionism, F/M, Fisting, Pegging, Tentacles, Transvestite, Voyeurism, pinescest - Freeform
Language: English
Status: Completed
Published: 2015-10-02
Updated: 2015-10-02
Packaged: 2018-04-24 12:22:57
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 13
Words: 19,821
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4919440
Author URL: https://archiveofourown.org/users/PineWreaths/pseuds/PineWreaths
Summary: <blockquote class="userstuff">
              <p>A collection of various prompt-based stories, all of them smutty and in no particular chronological/relational order. The tags refer to at least one story in the collection containing that subject; Let me know if you want me to post them separate in case there is a particular tagged subject you want to avoid while still being able to read the rest.</p>
            </blockquote>





	1. Sweet Dreams

**Summary for the Chapter:**

> Based on the prompt "One of the twins pleasures the other in their sleep. (the sleeper is either really drunk and they're not in a relationship yet or the sleeper consented first just cause its better. either one, or something dif, up to your expertise)"

Mabel let out an exasperated sigh as Dipper’s words trailed off into a mumble, and he started to snore. She rolled her eyes and huffed, starting to stand up before the world spun in a manner that made it clear that excessive movement was a poor choice given just how  _many_  Sex on the Beaches she’d ordered.

True, the first one was just because she loved the taste of the cranberries and peaches, but after seeing how Dipper had blushed over his IPA when she replied to his question of what colorful drink she’d ordered this time, she began ordering them just to mess with him.

She giggled, leaning back to floop onto her bed, draping over her unconscious brother’s legs. They had an evening with their parents out, and both being home from college they were away from their school friends; Neither twin had any real close friends in Piedmont, so they’d moseyed down to a hole in the wall out of the way when Mabel saw they had cheap well drinks;  _Grad student stipends mean beggars can’t be choosers._

Still, after both coming to the conclusion that the rum and coke Dipper ordered did indeed taste like it was made in a poorly-cleaned well, the twins had splurged on the nicer cocktails available. Almost an hour of carousing had led to a particular exchange that sober Mabel would never have said aloud, but happy-drunk Mabel was all too eager to initiate.

_“Dip. Hey, hey Dip. Diiiiippeeeeeer. Deerper. Dippingsauce. Dipdop. Di-”_

He had turned to her, snapping irritably but trying to keep a smile of off his face.  _“What?”_

 _“You…you wanna…wanna…”_  He had rolled his eyes, as she made the third identical joke in the last twenty minutes.  _“Wanna try some Sex on the Beach?”_

She had grinned as he let out an exasperated groan, and replied this time with  _“Mabes, there’s not a beach for miles around, and even if there was, beaches are wet and hot and dry and uncomfortable all around.”_

Before she could stop herself, she had spilled out in a husky voice  _“Well,_ I’m _wet and that’s normally all that matters.”_

She had cut off with a squeak, and Dipper’s alcohol flush suddenly evolved into something that looked like a rash as he pointedly stared into his drink. There were a few seconds of silence, and in a little strangled voice he’d replied  _“Well, yes, that would make basically everything else moot.”_

Mabel had said nothing, her brain having regained control of her libido and they thoughts she normally kept locked and barred and buried that alcohol had freed to cause mayhem.  Dipper gave her a look, one she didn’t recognize, and in a flat tone that held  hint of hesitation, he had spoken again.

 _“Um, but, well…are you…are you?”_  he finished awkwardly.

Mabel could feel her own cheeks catch the same burning rash of embarrassment, but something inside of her forced her to at least be honest with her brother, and she met his gaze, nodding with a shrug and a grin.

That was when she’d seen his expression change to one of relief, causing her own stomach to do an odd freefall into a cloud of horny butterflies, and he leaned forward, hesitant at first, with his lips puckered.

 

 

There had been a rush; A kiss, shy before bursting into fiery passion. A taxi ride, their hands excitedly running along each other’s bodies in the dim back; Stumbling into the house, Mabel thanking every archaic god, demon, and fae they had ever read about for their parents going to Reno that weekend and leaving the house empty; And then sitting on the bed, Dipper’s excitement overcoming his libido as he kissed her with sheer excitement over their mutual feelings being out in the open.

That was when Dipper’s lightweight status caught up to him, and he began fading as the weight of multiple pints in an evening began to make their rounds. Mabel had always been able to hold her liquor far better than her brother, a feat she attributed to the unnatural potency of a glass of Mabel Juice every week, or at least every week when her mouth and throat had sufficiently healed up from the last glass.

Dipper shifted in his sleep, rolling onto his back, squishing her stuffed unicorn doll as his legs kicked a bit at the sheets. She chuckled, looking over him as he raised an arm to scratch his head before mumbling as he dropped it, snoring quietly the entire time.

Her breath caught, and she began to feel the heat resurge from earlier; Dipper’s lifted arm had scooted his shirt up a little, and between the flannel and the denim there was a little two-inch gap of bare skin. She bit her lip, hesitating before running a finger along the skin above his hip, before stopping as it brushed against the happy trail of just-right hair below his navel.

Dipper let out a breath, and she froze, but he just smacked his lips a bit and shifted his hips a little. The quiet, almost imperceptible sound of adjusting fabric was heard between his snores, and Mabel’s eyes grew hungry as she saw the bulge of his jeans lift, ever so little.

Her free hand suddenly began exploring its way under her shirt and along her own stomach as she repeated the finger along Dipper’s exposed skin. Again, he shifted slightly, still fast asleep, and again the denim tented a bit farther.

She looked to her brobro’s face, smiling as she saw he had a tongue out, concentrating on some task in the dream apparently.  _Oh, Dip, I love you, and tonight was suuupeeer amazing for all kinds of reasons, chief among hem being that you loved me back._

Her gaze ran down his chest, past his shirt, and to the denim protrusion, as her hand slipped from running up underneath her bra to run down and slide under the elastic of her skirt, a finger slicking lightly along her wet lips.

_But, right now Mabel needs some, and I figure it’s only fair if I treat you right while I ogle for my own happytimes._

She lifted her hand up, and carefully, she unzipped his fly, having decided that dealing with his belt would have been too much of a hassle. Carefully, she pulled his cock out, freeing it to the warm air of her bedroom, sucking a breath in through her teeth as she saw her twin’s shaft, truly erect for the first time. Ever since puberty hit, they’d never really been naked around each other, and Mabel’s few attempts at “accidental” shower interruptions with Dipper had been foiled by opaque shower curtains and Dipper’s odd love for showering in swimtrunks.

She gently grabbed it, her hand returning between her legs as she carefully pumped him. He sighed, shifting again and letting out a little groan. Mabel’s breath froze, but she grinned as another snore escaped Dipper. As she moved her hand, she could feel his cock harden, the skin filling out and becoming something that put all of her varied and colorful dildoes to shame.

She dipped her fingers inside herself, running them around her clit while occasionally touching it as much as she dared, and she leaned forward on the bed. Already, a little drop of fluid had formed on the end of his member, and she carefully licked it off with the tip of her tongue, causing unconscious Dipper to raise his hips slightly.

She kissed his cock, and then engulfed it, feeling it fill her, inhaling his scent as her fingers worked herself furiously. She could feel her knees buckle, and she let out a little cry as she came, her vision crossing slightly as she carefully avoided using any teeth when she tensed.

_Whoo, that certainly is nicer than Mabel Happy Funtimes all by myself._

She sucked, running her tongue along the firm, uneven texture of his shaft, rubbing it in a little circle around the head of his member and giving it a little kiss as his hips shifted upwards again. Mabel hummed happily, before plunging back down again, her free hand that wasn’t busy between her legs running up under his shirt, feeling the smooth muscle tone against his lean frame, the sparse hair along his chest.

Suddenly, she felt his cock harden, pushing upwards against the side of her mouth, and she quickly prepared herself as his hips pushed upwards, Dipper moaning aloud as he came. He filled her mouth, and Mabel concentrated on gulping it down as it came, pulling off of him with a  _pop_  and smacking her lips. She didn’t enjoy the taste, but then again she wasn’t blowing her brother for the  _flavor._

She could feel her own heat building to a fevered peak, but not quite make it. Then she started, jumping as she felt another hand join hers between her thighs:

“Hey you.”

She started turned, guiltily towards her brother, but he just smiled sleepily at her. The smile turned mischievous as his hand pressed his thumb to her clit, rubbing it slightly as his other fingers played across her lips. That did it, and she felt fireworks as she let out a squeal, panting for breath as she shuddered, and groaned with release and desire.

She leaned back, sighing, and then leaned forward to kiss her brother. He returned the kiss gladly, but she could still see how sleepy he was.

He noticed her look, and gave her a reassuring wink. “While I think the hops have it in for me tonight, we have the house to ourselves tomorrow as well. We could take a road trip down the coast a little, and if you’re interested tomorrow…”

 

“…We could try some sex on the beach?”


	2. Roaring Fun

**Summary for the Chapter:**

> From the prompt "Dip and Mabes give cosplay a shot and are really into each others costumes."

“I’m telling you, I would have been too tall to play him”

Dipper shook his head, as Mabel huffed. They were giving their cosplay outfits a test run, and while Mabel had kept hers a secret so far, Dipper knew whatever it was, she was excited about it as she bubbled about, sneaking away in the evening to sew parts together.

Dipper stood in the full-length mirror, as Mabel was donning her costume behind a dividing panel. He held up the plaster gold hand, grinning and  turning to admire the silver armor and long white cloak. The two of them had just finished binge-watching Game of Thrones, and Dipper had decided that while he was too thin and prone to smiling to play the Hound, and not hairy enough to go as a Stark or Baratheon, with a bit of temporary blond hair dye and Mabel’s help in making the incredibly-realistic armor, he made for a surprisingly-accurate Jaime Lannister, Hand of the King.

Dipper had to internally restrain himself from doing a little happy jig; The costume even had a sword, something Dipper had secretly been wishing for an excuse to buy and carry since he was little.

Mabel cleared her throat, and Dipper turned attentively. He was expecting her to step from behind the divider in the baby blue of Daenerys, as she had been going on and on about the dragons every time they were onscreen.

However, as she stepped out from behind the divider in a long, flowing off-the-shoulder dress of red edged in gold, Dipper remembered suddenly how  _hungry_  their sex had been that night after they’d watched the first episode, and seen the two fictional siblings together in the tower.

She grinned, holding up a plastic wine goblet in one hand as she strode over to him, trailing her fingers along his arm. Dipper was amazed; Mabel had used a similar temporary dye to his own, turning her brown wavy locks a gold that almost matched the color trimming her dress, and made for a perfect cosplay for Cersei Lannister.

She stopped, her fingers resting on his stomach, just above his belt and codpiece, as she murmured “Oh, Ser Knight, I fear my bed will be an empty and lonely one this evening. Would you stay, and tarry with me until the morrow?”

She almost kept a straight face, letting out a quickly-muffled  _snrk_  near the end, and Dipper grinned, before catching himself and solemnly nodding. “Yes, my…my lady.”

Internally, Dipper was making a high-pitched screaming noise. While he would have died before admitting it to Mabel, part of what had started the whole ball rolling with him professing his feelings almost a year ago was diving into the book series, and discovering a relationship that was what he wanted so desperately to have.

Well, apart from all the torture and rape and murder and dismemberment.

_Actually, I could take the sex and leave everything else behind. Medieval-analog life was rough._

In any case, he had fantasized about something more or less exactly like what was standing before him for years, and his sister was giving him a look that made him, well,  _greatly_ appreciate that he’d overridden her protests and opted against having her measure and make him a codpiece for the armor.

Dipper leaned his head in, kissing his sister full on the mouth. Mabel let out an appreciative hum, tossing the empty plastic goblet onto her bed as she ran her hands up under his cape, scratching along the foamcore armor and pulling him to her.

He ran a hand down her side, feeling until he found a slit in the dress that ran up to slightly above her knee, The rogue hand traced it’s way up her thigh, Dipper loving the little shudders she made, as he reached her mound.

“Hmm, m’lady has been _expecting_  a knight it seems,” he murmured as he could feel a silky lace instead of the smooth cotton panties she normally wore. It also was a thong, judging by how he could run his other hand along and cup her ass.

Mabel, meanwhile, was making little urgent noises, her hands scrabbling at his waist. Dipper, keeping one hand rubbing her through her panties, moved the other to help her undo his belt and drop the pants and boxers; They pooled around his waist, his cock springing free as Mabel immediately grabbed it.

She began stroking his shaft, making Dipper groan, and they turned to look towards the bed-

Dipper chuckled as Mabel blushed in slight embarrassment; Various college homework assignments and costuming supplies were scattered across it, and Dipper saw enough glitter to stay  _well_ back and keep his so-far unblemished white cloak pristine

Still, her hand was insistent, and he growled, and spun her. Reaching his hands under her, he lifted her up, bracing her back against the wall. Trying to hide just how much exertion he was actually expending, Dipper used a thumb to nudge her appropriately-gold lacy silk thong aside, and slide into her.

Mabel hissed with pleasure, her legs wrapping around him, and he could feel her pull him deeper into her. He leaned forward, kissing her before trailing kisses down her neck and to the plunging top of her dress. She groaned, and Dipper nudged the fabric down with his chin, taking a nipple into his mouth and teasing it with his tongue as he pumped into her with a combination of hips and old-fashioned elbow grease.

He could feel her tense in a small orgasm, letting out an appreciative silenced moan, but feeling her body still rigid as she rode the cusp, almost over the edge for a big one. Dipper hadn’t had a chance to “relieve” himself earlier in the day and jerk off, so rather than fight the tide, he pulled her close and shuddered, his knees going weak and almost dropping his sister as he came.

She mashed her face against his, thrusting a tongue inside his mouth as she screamed and came, her body milking him as her legs pulled him as deep as he could be into her, then relaxing as the afterglow replaced the high. Dipper, for the most part, just focused on staying standing, and letting her down easily after a minute of just staying inside of her.

Their breathing had begun to slow, Dipper pulling up his pants as Mabel adjusted her dress and hair, when they both froze to the sound of their mother’s voice at the door.

_“Kids? You all right in there? I heard a thump or something on the wall, and just wanted to make sure your costume stuff was going ok.”_

Dipper, mind racing, called out with a forced laugh “Oh, heh, I just stumbled on my cape and caught myself. Nothing damaged.”

After hearing his mom reply,  _“Oh, good!”,_  he looked to his sister, leaning over to kiss her quietly on her pouting lips before continuing.

“I think these costumes are going to be  _perfect.”_


	3. Popcorn

**Summary for the Chapter:**

> Based on the prompt "Family movie night! Both twins are on the couch sharing a blanket. One starts teasing the other under the covers."

Dipper was determined that  _this_  time, he was going to win.

It had started off as just held hands, interlaced fingers to show their love for each other while hidden from the almost-certainly-disastrous view of their parents. Each Sunday, they had family movie night, where Dad would put on some film from his immense trove of DVDs, and they’d all sit together; Dad in his recliner, Mom in her rocking chair, knitting while watching, and Dipper and Mabel leaned up against the couch, their legs drawn up near their chests and with a blanket over the twins to protect against the chill.

And of course, nestled in between the two of them, the bucket of overbuttered popcorn.

Mabel had been the one to start making the moves, her hand breaking the laced grip and migrating to rub against his thigh at first, and then later teasing into his waistband to rub along his cock. Dipper had acted in kind, returning the searching hand to rub first on the outside of her thigh, and then on the inside, brushing against her damp panties.

He had been terrified they’d be noticed, but the two had managed to figure out how to cover the sifting hands underneath the blanket by reaching for another handful of popcorn and using that to cover any movement of the bucket.

However, three weeks ago, Mabel had made it a challenge. As they giggled together, brushing teeth after their parents had gone to bed, Mabel had quietly sidled up to him, double-checked that the bathroom door was shut, and reached around to rub a hand along the front of his sleep pants.

“Hey, brobro,” she’d said, giggling as he’d jumped in anxiety and glared towards the door as if expecting it to attack him without warning.

“Tonight was.. _.very_  fun. However, I can’t help but feel you’re slacking off a bit in the attentiveness and such.” Her tone was mocking, light, but with conviction she said “I feel that next Sunday, whoever fails to  _satisfy_  their partner first will have to give head as punishment that night. Do you accept?”

Dipper grinned in grim determination, and chuckled before saying “You’re on, sis. Hope you like the taste of defeat.”

She had chuckled, ducking down to pull down his waistband and plant a kiss on his suddenly-awakening cock, before standing back up and murmuring “I just wanted to give it a last taste before I start winning.”

Dipper rolled his eyes, chasing her into her bedroom and messing around a bit after they were sure their parents had gone to bed. He wasn’t worried; Dipper was positive he would win.

Dipper was wrong.

 

 

The first night wasn’t even a contest. Mabel had worn some skinny jeans, likely on purpose, and Dipper had barely gotten into them by the time she’d managed to unzip him, release his cock, and pleasure him enough that he could feel the start of the twinges of an inevitable orgasm. He had excused himself, citing dinner disagreeing with him as he ran to the bathroom, making it inside just in time to grab a tissue and come into it, shuddering and groaning quietly in ecstasy and defeat.

That night, Mabel had lorded her victory over him, and while they eventually moved from mere oral to him driving his cock inside of her as she made happy little gasps and pulled him closer with her hands and legs, afterwards Dipper had made sure to set some ground rules in terms of appropriate clothing.

Mabel had pouted but agreed, and the next week it was her in a skirt and Dipper in sweatpants. Their parents headed to bed early, and they began in earnest then. This time it was much closer, and he could hear her breaths starting to shorten, but Dipper could feel himself coming again. In the absence of their parents, Mabel ducked her head under the blanket, catching his orgasm in her mouth before swallowing.

She had given his flaccid cock a little loving pat afterwards, saying “Aww, I missed you little guy,” before winking at Dipper. The morning after that night, Dipper felt like he’d had his jaw tased, and Mabel complained all the next day of a slight itchy rash from his stubble, but they both grinned at the mutual griping and giggled later over breakfast to the amusement of their clueless parents.

 

 

Tonight, Dipper was in the lead.

They had come back from the pool, and Dipper was still in his trunks while Mabel was in her one-piece neon-pink swimsuit. The bucket of popcorn was where it should be, but the tighter-than-normal waistband and lack of a fly for her to unzip and detour directly to the goods had cost his twin precious time.

Meanwhile, he had been able to rub along her lips through the fabric almost immediately, feeling a dampness that was fresh rather than from lingering poolwater; Anticipation had already primed Mabel, and Dipper slid the wet fabric aside to begin rubbing his thumb in little circles around her clit.

Mabel’s legs clenched together, and he could see her neck muscles tighten as she strained to stay calm and put off the building arousal. Dipper could feel a slight tingle, but from his sister’s shortened, airy breaths he could tell she was going to come at any moment.

Remembering something he’d read a few months back, Dipper crooked his index finger, plunging it inside her to cradle against the soft, slightly-spongy area the website had described.

The effect was immediate. Mabel’s stroking of the “Little Dipper,” as she called it, reached a fevered pitch, and if it weren’t for the fact that the climax of the movie was occurring on the screen, Dipper was positive their parents would have noticed the climax of their daughter just a few feet away from them.

Her legs clamped together once, twice, as her breath caught in time. She hissed out his name quietly under her breath, drawn-out as the orgasm diminished:  _“Diiippeeer”_

He grinned in triumph, before a moment later his eyes widened in shock as he could feel himself coming. Mabel’s ministrations had flagged only slightly as she came, and it seemed she was determined to get her brother off no matter what.

He shuddered, a leg spasming slightly as he came, and what his mind had been frantically trying to warn him about became apparent; As the final pulse jetted out, Dipper could feel that the entire front of his trunks were warm and sticky with his cum, as was his sister’s hand, and probably a not-insignificant amount of the blanket and floor he was sitting on.

Sitting there in shock, Mabel equally still as she realized the implications as well. The film finished, and Dipper’s heart sang as their Dad chuckled, saying “I always forget how much I love this series. Who wants to watch the next one?”

Their mother’s reply of “It’s getting late, dear,” was drowned out by the twins’ mutual shout of “WE DO!”, and both parents chuckled and sat back down as the menu screen popped into place for the sequel.

The twins sat back, and Dipper’s mind raced:  _Well this is certainly a proper mess._  He looked at the bucket between them, chuckling bitterly.  _And to top it all off, we’re out of popcorn._


	4. That's Knot Funny

**Summary for the Chapter:**

> Based on the prompt "Camping trip. Twins leave for a week into the woods to have some fun."

After almost two solid months of pleading, Dipper had managed to convince his parents to let him borrow one of the family cars for spring break. He had gone on relentlessly about how he’d missed his days of Wood Ranger campouts, roasting marshmallows, hiking along forest glades, fishing in untamed rivers, and all the other outdoorsy awe-inspiring imagery he could conjure.

Truth be told, Dipper hadn’t been happier when his parents had allowed him to quit the Rangers all those years ago; Campouts with them always seemed to consist of more whining and beg-filled tents and sleeping bags than fun adventures, and the glamour quickly wore off after the first half-dozen campouts.

Still, while his newfound interest wasn’t  _entirely_  faked, most of the prompting came from Mabel, who showed mild interest publicly, while feeding him lines about “fresh mountain air” and “eating huckleberries right off the bushes” to sway their folks. They wanted the week all to themselves, and Dipper was counting on this camping trip as their way to have a week all to themselves.

Finally sighing and rolling his eyes, their dad caved, with barely a week to go until break began. Mabel had almost-apathetically asked if she could come, and Dipper successfully acted happy but otherwise indifferent, doing cartwheels of excitement and relief internally as their parents barely batted an eye when she said she’d be accompanying her twin on the trip.

Mabel prepped their supplies, getting two backpacks filled with snacks, freeze-dried food, sleeping bags, a change of clothes, a change of naughty lingerie buried discreetly beneath the clothes and inside of a cookpot for good measure, and various flashlights, first aid kits, water bottles, and other sundries.

Dipper, citing “special Wood Ranger training,” had made a trip to the  _Home Dictator Supply Store_  and got a single large item that he brought back in a brown paper bag, shoving it at the bottom of his pack before sisterly curiosity could spoil the secret.

They had raced home after that Friday’s bell had rung, signalling the start of the last spring break they’d have in high school, and peeled out of the driveway barely ten minutes after getting home, giving their parents brief excited kisses on the cheek before hitting the interstate.

The drive was only two hours or so, counting breaks to pull off to rest stops for kisses and heavy petting they had to abstain from at home, but the hike into the remote site was another hour, and the light had almost faded when they finally got their tents erected. They’d grabbed food on the road, and so tired and sleepy, they had to cut the kisses and gropes short, tucking into their sleeping bags.

Dipper, his mind racing with anticipation, leaned over to his twin before she fell asleep. “Hey, uh, Mabes?” he said with a sudden burst of gut-wrenching nervousness.

She grinned, her braceless teeth shining in the dark. “Yeah, brobro?”

He smiled softly, and said with a bit more conviction “I, uh, I have a surprise for you, for tomorrow.”

She giggled with excitement, wiggling in her bag, and said “Is it in the bag of doom you forbid me from peeking in?”

He nodded, and continued solemnly. “The thing is, um, it’s a safeword-y kind of surprise. Is…is that still going to be okay to surprise you with?”

Mabel narrowed her eyes in thought and trying to suss out her brother’s plot, but she had nothing. She shrugged, grinning and saying “Sure, brobro. Fistbump’s the word if stuff gets too intense, right?”

He nodded, kissing her briefly before flopping back into his bag, letting out a breath of anticipation he hadn’t realized he’d been holding.

So far, everything was going according to plan.

 

 

Mabel woke up slowly, groggy as she could feel a bit of a breeze blow over her-

_I’m naked and outside. Why am I naked and outside?_

Instinctively, she went to try and cover herself, only to find her arm was refusing her. It was stuck, and looking down, she could see coils and coils of soft nylon rope looping around it, gently but firmly binding it to her other arm behind her back. Her calves were bound in the same way to her peach-cream-colored thighs.

Shifting also made her aware of the sensation of friction along her body as well, and she could see a network of crisscrossing diamonds spanning her chest, each big enough to permit one of her small but ample breasts, nipple standing at attention as another colder-than-was-preferable spring breeze drifted past.

The rope dove between her thighs, on either side of her mound as it massaged either side of her lips, before running up her ass and tying back up to her neck like a laughably-inadequate swimsuit.

The sound of a snapping twig brought her attention to her side, where her brother strode out. He was missing the jeans and flannel that was practically his uniform nowadays, and instead-

Mabel let out a happy whimpering growl of approval. He’d managed to conceal and bring a pair of long, black silk sleep pants, the wind flattening them to his legs and showing off the not-inconsiderable muscle tone he’d built from running into and out of trouble for all those years at the Shack.

In one hand he held what looked like a cat toy; It  _technically_  was one Mabel had bought for the fun colors and jangly bits, but a few weeks back Dipper had grabbed it while she’d been blindfolded and handcuffed, utilizing it to great effect in teasing the heck out of her. The dangly jingle-ball was gone, leaving just the flexible whippy stick and the purple pouf of feathers on the end.

In his other hand he held a lumpy length of rope identical to that wrapped around her, and Mabel saw that there were multiple strands leading from her, tied into a single braid that went over a waist-thick tree branch about fifteen feet up, before trailing back down to her brother’s hand.

His grin made her tremble, and she licked her lips in anticipation as he said “Morning, Mabes.” He took a few steps over to her, leaning to plant a kiss on her forehead. She let out a little moan, leaning towards his cocks obvious outline against the silk pants before he pulled away.

Her brother tutted, wagging a taunting finger at her as he said “Now now, it’s improper to receive before  _giving.”_

As he said that, he hoisted gently on the rope, and Mabel could feel herself being lifted up by her arms and legs. Dipper had done his homework well; They had only experimented once with rope bondage, with Dipper reading off of an open webpage on his laptop as he tied her hands in a simple cuff and did some fancy squeezy thing around her breasts before they ran out of rope. But he’d tied something wrong, and after just a few minutes her arm started to fall asleep and they’d called it off.

This, however, felt more like she was cocooned in a personal hammock, and Dipper had rigged it in such a way that gravity gently nudged her legs to splay open, revealing herself to the woods as she spun gently with the breeze. Dipper stopped her, and just gave her a smile as she spun softly past him, holding up the toy to tease the feather along her as she spun helplessly. She giggled and cooed, but then gasped as he took a few crunching steps forward and kissed her clit, almost gently. Her legs thrashed, fighting against the suspension as he ran his tongue along her lips, gently probing into her before withdrawing to run little circles around her.

His hands weren’t idle either, and he began to run them along her sides, reaching up to tease at her nipples before cupping her ass. One let her suck on his fingertip for a moment, Mabel savoring the small appreciative moan he made and then shuddering as he hummed and sucked against her clit. Dipper moved his free hand up beneath his chin, and slid a finger into her, carefully angling it so it his _just_  the right spot, and Mabel felt stars as she tensed and shuddered for the third time in as many minutes.

Dipper didn’t stop, and soon the stars became supernovas of fireworks as she let out a muffled shriek, instinctive behavior from silencing her orgasms at home fighting against knowing they were the only people for ten miles and her raw, animal need to show her lover some verbal appreciation of his efforts.

Dipper leaned back, grinning, and gave her a pat on the leg. “Did you want to help me out with  _my_ problem now?” he said teasingly, and Mabel just nodded and gasped _“Uh-huh, oh god yes.”_

He leaned forward, carefully adjusting some ropes on her back into new positions, Mabel staying suspended the entire time. In the afterglow, she looked over the ropework with an appreciative noise. “You’ve really been practicing your Wood Ranger lashing skills, huh Dip.”

He chuckled, and just said “See for yourself” as he released a knot. Mabel let out a giggling shriek as she swung upside down, the weight now mostly hanging from her legs, but balanced out in such a way that it was like she was hanging from monkeybars at the gym instead.

Dipper’s erection was inches from her face, hidden from her by a thin layer of silk, and Mabel licked her lips in anticipation, when she saw a faint hint of movement out of the corner of her eye. 

Squinting, she tensed in horror as she saw the distant specks of a quartet of hikers, headed this way. The twins had camped basically right on the trail, in an area bordered by a pair of steep scree slopes, and the tree and brush cover here was borderline nonexistent.

“Fistbump!  _Fistbump!_  Ah, screw it; Dipper get me down,  _pronto!”_

Her brother obliged instantly, gently lowering her to the ground and starting to undo the knots as he spotted the hikers as well. Mabel kept watch, but could see the hikers were going at a solid pace, already looking like individual ants through the gaps in the bushes rather than colored specks.

“There’s no time,” she hissed back, interrupting him after he had only removed the aerial tether ropes, and making a tentative failed attempt to crab-walk on her elbows and knees. Dipper leaned down, scooping her up, but then turning to run behind part of an overturned tree’s rootmass.

“Dipper! What are you _doing?”_  she hissed, cutting it off abruptly as voices from the hikers began to be audible. He set her down, peeking around the corner before ducking back quickly. Looking at her apologetically, Dipper shrugged. “I had, uh, another ‘surprise’ set up in the tent. It’s closed, so they probably won’t mess with it, but that’s why I didn’t just hide us in there.”

Mabel rolled her eyes, but gave her brother a grin. “Well, until those interfering butts buzz off, I think we’re stuck here.” She licked her lips, looking her sweat shining on her brother’s body appreciatively as she bit her lower lip in anticipation.

She purred. ‘Now where were we?”


	5. Horny Ghosts: Washed Out

**Summary for the Chapter:**

> An alternative ending to this story: http://archiveofourown.org/works/4915615
> 
> Based on this prompt: "Alternate ending to chapter 3 of Horny Ghosts. A minor fire in a garbage bin sets off the sprinklers at the mall. Run, you two, run!!"

Mabel had pulled them into one of the empty dressing rooms, pulling the door almost-closed so a passerby wouldn’t see a floating bra and panty set, but not enough to make the employee think someone might still be in there. Dipper had wrinkled his nose in annoyance as he heard a pair of girl’s voices from a few dressing rooms down. They were quiet, full of giggles, and the pungent skunk-stink he recognized made him roll his eyes and try not to cough.

She murmured “All righty, Dip, turn around for this one.” He did as he was bidden, looking towards the wall, and could hear the rustling of paper, and several zipper noises as well as the sound of cloth sliding on skin, before a little timid voice said “Okay, you can look.”

He turned, and felt his heart skip a little, before warming with loving sympathy for his sister. The outfit accentuated the edges of her curves wonderfully, as did the fishnet arm warmers, stockings and black kneehigh boots she’d conjured out of nowhere as well. However, while it was hard to appreciate the lingerie on an invisible form, Dipper could hear her gasp and turn. He stepped forward to peek over the top of the dressing room door, and groaned.

The two girls had disappeared, leaving their still-lit blunt behind in a trash bin. Some old discarded receipts had taken objection to the ember present in their midst and burst into small, merry flames. The trash can was metal, and Dipper was fairly certain it couldn’t spread, but the fire was creating a visible grey ribbon of smoke upwards.

“Oh  _shit,”_  the twins said in unison before the sprinkler systems snapped on, alarms blaring as they could hear the employee at the counter for the lingerie shop begin swearing and running for the exit.

Mabel’s head was already becoming visible as the magical waterfall’s effect washed away, and Dipper held up a splotchily-visible arm  with a groan as well. After a couple tense seconds, his sister hissed  _“Go! Go!”_  at him, waving her hand as he sprinted into the shop, feeling a full-body blush fighting against blood-drained embarrassment as he realized most or all of his nude form was probably visible flopping about.

He screeched to a stop behind an abandoned kiosk as the sprinklers continued their merry rain. Mabel was right behind him, her black sheer teddy slicked to her form, although the water now just accentuated the black rubbery material of the boots. Dipper could feel himself starting to feel a warmth down below in spite of himself, but snapped his eyes back to the entrance. There was a huge crowd just outside the door, the refugee customers and employees of the mall shops.

He groaned in desperate hopelessness. “Man, Mabes, we’ll _never_ make it out without getting spotted.”

His mind began to whir with possibilities for breaking a window and rappelling to safety with some makeshift rope, when Mabel grabbed his shoulder, spinning him as she pointed.

“Look, where the Hoo-Ha’s was; An emergency exit!” Sure enough a looming grey double-door was visible, tucked behind a trio of other little temporary kiosks, and the small shrine erected to keep the former area of the damned animatronic amusements sanctified and uncursed.

They ran for it, with Mabel shooting Dipper a glance. Even mostly-flaccid, she was very much enjoying seeing his “Little Dipper” again, and from how it twinged when he shot her looks, he was appreciating it too.

They came up short on the door, screeching to a stop in the puddles. Dipper just strode towards the door, but Mabel still stood, and in a little playful voice said “Where’re ya going, Dip Dot?”

Dipper turned, confused, and then swallowed as he saw she had straddled a massage chair, her boots on either side matching the fake leather of the seat. As he watched, she winked saucily at him, leaning back to stretch and lift an arm lazily over her head.

_You know what? Fire Department responses for stuff like this usually take a while._

He grinned, striding over to his sister to grab her hand, lifting her up and hugging her tight as his lips engulfed hers. She sighed, giggling, and he could still taste a trace of the vanilla-bean lipgloss as he sucked on and released her lip. Mabel pressed her damp form against his, a hand running over the top of his thigh before wrapping around his cock and giving it an appreciative pump.

Then she broke the kiss, cackling as she pushed him gently to sit and lean back in the massage chair. Dipper did, smiling and sighing as she straddled him, rubbing her warm, wet lips along his shaft while she trailed kisses up his chest. Dipper groaned, pleading without words in the sound, and his hips rose to meet hers.

Mabel kissed him on the nape of his neck, the heat causing him to shudder as she drew back and the cold sprinkler water froze the spot. She then lifted herself up, reaching a hand down to guide her before sitting to settle on his shaft, her hips bumping against his as he filled her.

She moaned, leaning backwards to pull his hands up to her breasts. Dipper nudged the cups of the teddy aside, thumbs playing with the nipples as she scratched her fingers down his chest. Dipper’s hips rose to meet hers, and Mabel groaned, slowing and grinding against him between sets of lifting up to settle on and around his member. When he rose forward and gently nibbled one freed nipple, she had gasped, tightening around him, and letting out a happy growl.

A few more minutes, and she had come again, harder this time as Dipper’s breath became ragged. Mabel dismounted, quickly ducking down to suck on his cock, the sudden shift from heat of her body to cold water to the heat of her mouth causing Dipper to cry out, clenching the handrests of the massage chair in a deathgrip as he came into his twin’s mouth.

Mabel just made a happy hum around him, causing him to twitch again inside her mouth, and with a final suck and stroke of her tongue, she swallowed, and gave the head of his Little Dipper a kiss, before kissing him on his birthmark.

There was a distant sound of voices, and in a flash Dipper and Mabel were standing, the afterglow fading. Dipper looked towards the grey door, abruptly aware that there might be someone, anyone, a whole  _crowd_  of anyones outside.

His sister noted his worried expression, and her eyes came to rest on one of the racks at a kiosk with an evil grin. Dipper sighed, letting out a defeated groan, and then grabbed a costume

 

 

They burst through the door into the bright sunlight of the dilapidated area behind the mall. They were alone, and Dipper sighed in relief. He pulled awkwardly at the wet, far-too-small blue sailor scout tunic and skirt; They didn’t have a lot of options, and he had thoroughly shot down Mabel’s joking proposal when she held out the Slave Leia costume from the Summerween costume rack.

_Although, that gives me all sorts of ideas for fun later this summer._

He followed his sister as she ran for the treeline, Dipper appreciating the occasional flashes he got up her identical undersized pink skirt as they ran towards their clothes and the location of the enchanted invisible waterfall.


	6. Coin Flip

**Summary for the Chapter:**

> Based on this prompt: "Pegging or hypnosis. Thanks!"

Mabel cackled, as Dipper threw up his hands in frustration. “Heads, again? Seriously? What are the odds?”

She glanced to one side, the cackle fading slightly before she cleared her throat and put the flipped coin back on the nightstand. “A deal’s a deal, brobro. So, you have your pick this lovely evening,” as she rustled around in a drawer, before finding three items to stack in a row on her dresser.

“Would you prefer the MabelToo, the Mabelinator, or the Big Dipper?”

Her brother swallowed, groaning as he surveyed his options. The “MabelToo” was a purple dildo, only two or three fingers in diameter, and had a hooked bulb around one end that allowed her to slip it into herself and join in the fun. In contrast, the “Mabelinator” was as big around as his wrist, and an ominous jet black that seemed to mock him.

Lastly, the “Big Dipper” was, according to Mabel, supposedly modeled off of pictures taken of his own “Little Dipper,” but then enlarged and sculpted before she’d poured it herself. It was purple, filled with glitter, sequins, and he’d have sworn he saw a plastic dinosaur hiding in there somewhere. It was also the diameter of Dipper’s own forearm, and made him sore just looking at it; He was 95% positive she made and kept it just to mess with his head.

For the fourth week in a row, Dipper pointed towards the MabelToo, still unwilling at this point to risk the Mabelinator, and she squealed and grabbed it. They’d been fooling around in her apartment before the fateful coinflip, and so she was able to slide the purple shape into herself without much apparent effort. Grabbing the bottle of lubricated jelly, Dipper sighed, grinning despite himself when he thought Mabel wasn’t looking and squirted a generous portion on his ass.

Scooting up behind him, Mabel ran a hand along his back, running to his thigh as her other hand adjusted and aimed the purple silicone head.

“Ready brobro?” she murmured, and he nodded.

She pushed, gently at first as the head slipped into him, pushing past the ring of muscle and sliding with the aid of the jelly. Dipper arched his back a little, the moment of pressure and pain replaced by the incredible fullness. He let out a little caught breath, and Mabel began to draw herself out smoothly, before sliding back into him.

As she continued to pump, speeding up the motion, the dildo bumped against her clit too, the clever angle of the bulb inside her rubbing against her clit as she pushed into her twin, and pressing on the spongy sensitive mass of her g-spot on the withdrawal. Her breath was catching, and she ran a hand up her side, squeezing and tweaking a nipple. Dipper, meanwhile, was just panting into a pillow, arching his ass upwards to her and now pushing backwards on the stroke against her.

She ran her hand from where it was bracing on her hip to reach around and grab his cock, pumping it as she thrust into him from behind. Dipper let out a little strangled whimper, gasping for breath as he muttered  _“Harder, oh god please Mabes harder.”_

His begging did not go unheard, and she sped up, slamming into him as hard as she could, whimpering herself as the dildo worked its magic on her as well.

She suddenly felt him tense, his hands grabbing and scrunching up the comforter, as his cock pulsed and he came onto the awaiting towel they’d laid out. She continued thrusting hard, each stroke into him causing him to shudder and drip again, his voice now a surprisingly high-pitched moan punctuated by gasps of breath that matched her thrusts.

His voice and her own stimulation sent her over the edge, and she abruptly stopped, pulling out with a _pop_  as she yanked out MabelToo and completed the job with her eager fingers. She let out a squeal that disappeared into a moan as her brother kissed her, matching her moans with his own as they sunk into a mutual afterglow.

 

 _That was a close one,_  she thought as she cleaned up later, tucking the coin away into her dresser alongside the cleaned-up MabelToo and the unused intimidating behemoths _. I think Dip doesn’t suspect anything, not yet._

She grinned to herself.  _Grunkle Stan taught me that weighted coin trick well._

 

 

 _That was a close one,_ Dipper thought, as he saw his sister put away the coin. The third night she’d won the flip, he’d absconded with it from her bedstand while she was out with friends one evening, and ran enough flips of his own with it to determine that either Mabel’s luck was akin to being struck by lightning while winning the lottery, or she was using a weighted coin.

He’d carefully replaced the coin that evening, with no regrets, and didn’t dare bring up that Mabel always,  _always_ chose Heads for the flip.

He didn’t want the fun to end, at least not yet.


	7. Spin the Bottle

**Summary for the Chapter:**

> Based on this prompt: "College Party. The people don't know the twins are related, spin the bottle gets out of control. (Its funner if its a sex themed spin the bottle / party, and maybe the twins aren't together yet.)"

While the classes were nightmarish, the food court’s “food” was terrible, and the dorms were overcrowded, seeing the third set of girls striding by in lingerie containing enough cloth between them to make perhaps two small napkins reminded Dipper why he loved college.

At least, that was what his macho go-get-em part had urged him to do. Mabel had inherited most of the forwardness of the two of them, but occasionally he’d channel his other half and do something impulsive rather than finish his calculus homework early, again.

However, the flier his roommate had given him, plastered with the words “LINGERIE PARTY” in two-inch block letters, had finally given Dipper the urge; Tonight, he was going to put failed dates and never getting past third base behind him.

 

 

That had been the plan, at least. However, his own shyness meant he was mostly ogling without trying to stare, amazed at the variety of beauty walking past. He also felt incredibly self-aware, as his shirt was lying in the corner of a windowsill, near the pile of other shirts and discarded jackets. The “No Shirts, No Service” poster at the entrance meant he’d had to discard his familiar flannel, and his lean body felt puny with the football players and wrestlers walking around, glistening from sweat in the warm room.

He didn’t recognize anyone, as they’d all been issued a colored opera mask to wear as part of the “mystique,” Most of the jocks he saw hadn’t bothered, wearing it like a pair of sunglasses on their forehead, but Dipper gladly grabbed a blue one to cover his eyes and his unmistakable birthmark.

As a result, Dipper was caught by surprise when a set of arms grabbed him, dragging him into a side hallway and down to a side room in the house. It was surprisingly spacious, and his the two girls who had grabbed his arms were giggling, the leopard print corset on one holding some very appealing mocha curves, while the other girl had a canary-yellow nightie and matching thong that hid little and flaunted everything else. When they turned and asked him if he wanted to play Spin the Bottle, his mind temporarily blew a fuse, and he blurted out “Sure!” as he followed them.

The room had a surprising number of people, nearly a dozen including Dipper, and seeing him a third girl in a purple mask and matching strappy teddy that made him even harder than he was already. There were four other girls, and a quartet of guys in addition to Dipper. He felt an immediate sigh of relief; The other guys weren’t ugly, but at the same time they weren’t chiseled greek gods like the sportball players out in the main part of the house, so Dipper didn’t feel like he was going to be outmatched.

He sat cross-legged like the other guys, still glad of his jeans helping to fight his raging erection, as the girls did likewise. The one in the yellow nightie stepped forward, carrying a hat and an empty glass coke bottle, setting the bottle down ceremoniously on the wood floor. She drew a slip of paper, reading aloud.

“Okay, so the first spin of the evening is: _‘Kiss your partner for a solid minute, with thirty seconds on the face, and thirty seconds…not on the head,’”_  she said with a wink to all assembled. The girls mostly giggled, and a few of the boys let out chuckles, as she grabbed and spun the bottle. It scraped on the floor, coming to rest pointing almost directly away from Dipper, towards the girl with the purple mask.

Then it was spun again, and with agonizing slowness, finally came to rest pointing at Dipper. He swallowed, wetting his lips nervously as the girl strode over to sit next to him. He looked into her eyes, the dim light making it hard to determine the expression in her eyes, but he leaned forward, and met her lips.

A little bit of the back of his mind, where his dirty thoughts were filed, noticed that the girl was wearing orange-creme lipgloss, the same as his sister Mabel wore. Dipper had oftentimes fantasized about kissing  _her_ , even once stealing her flavored chapstick and feigning innocence when she’d asked about it in confusion the next day. He had a  _very_  good time with his fantasies when he’d tasted the chapstick then, before the surge of guilt and shame made him throw it away the next day.

This time, however, he could imagine that he was kissing who he’d always wanted to kiss, and the thought burned away his inhibitions like a blowtorch, the kiss going from timid to full-on passionate as the girl opposite him gave an appreciative humming moan and responded in kind.

He had just started to run his tongue along her wonderful orange-y lips when the girl with the yellow lingerie ducked her head in, shouting gleefully “ _Time!”_  Dipper and the purple-masked girl jolted apart in shock, and he could feel a flush envelop his neck and cheeks when he became acutely aware of how many other sets of eyes were on them.

“Not done yet, though,” the nightie-clad girl announced, waving a stopwatch at them. “Now you have thirty seconds with no kisses on the face,” she said, waggling a finger. “Little Boy Blue, how about you go first?”

Dip nodded, and after a moment of hesitation, leaned in and planted a kiss on the nape of the to her girl’s neck. She took in a little breath, and pressed her body towards him. Taking this as an encouraging sign, Dipper began trailing little kisses all along her collarbone, daring to follow them down between her breasts as she let out little happy hisses of breath. The crowd around them wa making appreciative noises too, and Dipper’s eyes nearly bulged out in surprise as he saw more than a few pairs of hands in pants or under panties as they occupied themselves.

He led the kisses down her flat stomach, between the purple strappy ribbons of the lingerie, and along the side of her ribs, ending the circuit behind her as he continued up an exposed shoulder blade and ended with a long sucking kiss on the nape of her neck again, just as the announcement  _“Time!”_ rang out.

His partner growled, and spun around. Before the timer even started, she had kissed aggressively, leading her head down to the top of his little happy trail almost immediately. While still kissing, sucking, and even giving him light nibbles along the top of his hips, her hands worked the zipper of his pants. Dipper leaned back, eyes shut in sheer happiness for a moment as he heard a few of the girls giggle and the appreciative and envious nods of a few of the guys as he looked back down.

His cock free, the girl had immediately sucked onto the tip, running little kisses down his shaft, making him twinge and gasp. His hips shifted as he tried to lean back to give her access, propping himself up on his elbows as she kissed in a little circle all around the head of his member, before leaning down and giving him a long, sucking kiss down most of the length, making him groan as they both heard as the announcement  _“Time!”_  sounded for the last time.

As the girl went to lean back, the edge of the string for her mask caught his belt, and popped it gently loose. She blushed as she met his eyes, and Dipper’s stomach dropped into a pit of acidic butterflies as he said “M-Mabel?”

Her eyes widened, as she leaned back in shock, then leaned forward and eased up his own mask, gasping as she saw his birthmark. “Dipper!”

There was dead silence for a moment, and then one of the the other girls, who was wearing a tiny seafoam blue french maid outfit, lifted up her white mask, and said “Dipper?”

His eyes widened in shock and slight confusion. “Pacifica!” He looked to his sister, who nodded, but they both turned as they saw one of the boys pull off his grey mask, saying “Pacifica?”

In unison, the twins said  _“Soos?”_  as he shrugged and gave them an awkward grin and shook his head, in the process jutting out his chin and shaking his short hair into a brown mullet. In a horribly familiar voice, he said “Kids?”

 _“GRUNKLE STAN?!”_  the twins and Pacifica said in unison, and a little giggle rang out. Dipper looked at the offending giggler, the girl in the yellow outfit, as she smiled and took off her mask. Dipper frowned in confusion; He certainly didn’t recognize  _her._

She pouted, and then squinted, puffing out her cheeks. With an unsettling squelch her eyes slid across her face, merging into a single first-sized white orb with a slitted pupil dominating the middle. Grinning, she giggled, the sound much deeper this time, and in a familiar nasal tone said “Remember me now, Pine Tree?”

 

 

Dipper woke up screaming, thrashing in his bed for a moment while muttering  _“Bill Bill Bill Bill Bill Bill…”_  as he looked around, his eyes wide. After a long moment, he saw the  _2:03 AM_  on his clock, and flopped back into bed groaning. For some reason, he was now  _very_  apprehensive about attending the party tonight.

But, as he rolled back over and thought of trapping Bill in a little jar filled with angry hornets, he now had some distinct hopes that a certain purple-masked girl might be attending.


	8. I Spy

**Summary for the Chapter:**

> Based on this prompt: "for smutmas could you do one where dipper and mabel get caught but whoever caught them is fine with them being together"

_“Seriously?”_

Dipper and Mabel froze, although Dipper could feel his body urging him to keep thrusting, and ignore the face of Pacifica that peeked out at them from behind the opened picture frame. Mabel let out a little awkward giggle, waving her velvet-gloved hand at her and saying “Uh, hi Pacifica. S-Sorry we ducked out of the party downstairs.”

Pacifica glared at them for a moment longer, and Dipper could feel her eyes following up and down his half-naked form. Mabel’s legs had come up a bit in modesty, but her dress was still sandwiched up around her waist as she lay on her back in the dusty storeroom.

Finally, their host let out a groan, rolling her eyes before looking away. “Ugh, fine.You’re obviously _busy_  at the moment, so just make sure you’re back downstairs in time for the gift exchange, all right?”

Dipper nodded with his mouth still agape, the little plush santa hat on his head slipping the last of the way off of his sweaty hair to land in a heap on the floor. Mabel nodded as well, but as Pacifica went to leave Dipper called out “Um, Pacifica?”

She stopped, pointedly staring at the wall to the side of them. _“What?”_ she said, sounding peeved again.

“Um, so, Did you  _know?_  About, uh, _this?”_ he said, gesturing generally around at his sister and himself.

Pacifica just rolled her eyes, and as if she was reciting from a list in her head, said “Dipper, you always forget to wipe the last bit of her lipstick on the left corner of your mouth. If you guys were getting particularly involved, you always have glitter on your hands and pants. Mabel, your cheeks and neck get especially pink afterwards, I’m guessing from his stubble, and several times you’ve forgotten and left your hair up in a ponytail.”

Dipper and Mabel both looked at each other, and then to Pacifica. “Uh, wow Paxy,” Dipper said, a note of awe in his voice. “You’re better at picking up clues than your Mystery Twin teachers, apparently.”

She smiled primly, but then turned, closing the painting and saying through the thin canvas “Don’t forget the gift exchange!”

Hearing her walking away, Mabel scooted out from under Dipper. “Wow, brobro, the student has become the master.”

He sighed, sitting back on the dusty wood, grimacing at the now-thoroughly-flaccid Little Dipper with dismay. “Yeah, I guess she really did.”

Mabel scooted over to him, army crawling on her elbows, putting her head in the perfect position to plant a little kiss on the top of Dipper’s shaft. “Now, where were we?”

 

 

Pacifica had not headed back to the party, and instead made a distinct detour towards her father’s study. There, she opened it up, striding past dead stuffed animal heads on every wall as the snow gently fell outside, thankful that her parents were out on a cruise at the moment. Cracking open the door, she was greeted by a dull green glow suffusing the room, gently flickering as the light of nearly two dozen security camera monitors lit up the room.

She sat in the black leather swivel-chair, clicking the door shut and locking it behind her, as she spun her attention to the monitors. The displays all bordered a huge screen, one that would have made any home theater system proud and currently displayed a map of the house with flashing indicators corresponding to each of the cameras locations.

Well,  _most_  of the camera’s locations. She had paid the contractor an extra couple grand out of her allowance to install a trio of extra cameras without her parents knowledge, and entering the secret key combination on the screen, she pulled up and enlarged the three feeds to take up the entirety of the large display.

With a slightly-shaking finger, she glanced back to the locked door before gingerly pressing the _“Unmute”_  button.

The moans of Dipper and Mabel filtered through the audio pickup, and Pacifica sat forward, her eyes drinking in the twins as they thrust against each-other. She was suddenly _very_  thankful that her parents had spared no expense in the brand of cameras the contractors had installed, as the detail was so good she could make out the markings on Dipper’s forehead and the sweat along his shoulders. He had discarded his shirt, now naked in his sister’s embrace, and Pacifica could feel herself growing wet as she watched.

Carefully, she began to rub a hand along her side, her eyes still glued to the siblings on the screen as it traveled up and down the puffy blue silk. She reached the side of her bust, and ran the palm across her breast, massaging and rubbing at it slightly as her other hand started to drift away from the camera control panel.

Mabel had sat up, kissing her brother deeply, before saying something so quiet Pacifica couldn’t make it out. Dipper withdrew, the sight of his shaft still wet from his twin casing Pacifica to shudder. The hand that had been slowly venturing towards her thigh shot there in a heartbeat, frantically shifting chiffon and taffeta aside as she watched him sit on his back.

Making a happy giggle, Mabel clambered over to straddle her brother, slowly lowering herself, and Pacifica reached her panties, sliding the white satin aside to touch  _there,_  and she arched her back, letting out a little pant as her fingers began to push and orbit her clit. She scooted forward in the chair, spreading her legs to permit herself as much access as possible, and the hand that was running over the top of her dress shoved the fabric aside, as she grabbed her herself, running her hand across her breast and tweaking her nipple.

On screen, Dipper was grunting with exertion, lifting his hips in time with his sister’s downstrokes, as Mabel slammed down hard on him again and again. Pacifica was looking up as much as she could manage, but both the angle and her own arousal made doing anything but shutting her eyes and stimulating herself seem like a laborious effort. Instead, she leaned back, lifting her leg up to brace against the console edge as she worked herself, dipping one finger and then two into herself, tentatively exploring before coming back to rub and tease her clit.

Her ears burning, she concentrated on the sound of the twin’s labored breathing, of Dipper’s grunts, the sound of their bodies impacting, of Mabel’s little gasps and happy whimpers and the rustle of her dress against the floor. Pacifica’s imagination put her between the twins, Dipper slamming into her as Mabel explored her mouth tenderly. She hissed out a breath of pleasure, a whimper to no-one as she shuddered, but her imagination wasn’t done yet.

She adjusted her leg again, and this time it was Mabel between her legs, her tongue flicking along Pacifica’s thighs, teasing before sucking on her clit, crooking a finger inside of her before running little happy circles around her clit with the tip of her tongue and nimble fingers.

Meanwhile, Pacifica’s mouth was engaged by Dipper’s kiss now, only to be replaced as his musky taste withdrew, and was replaced by his warm member, practically begging for her to take it into her mouth. She did, engulfing him as she sucked, working her tongue along it like she had in so many other fantasies, imagining him tensing, groaning as he came into her mouth. She gulped air, gasping as she came, letting out a moan of “Oh  _god,_  Dipper…”

In the afterglow, she started to sink into her chair, eyes still happily shut, only to stop and peek an eye open when she noticed the lack of the twins’ happy sexytime noises.

She froze in horror, as she saw they were both standing, Dipper’s cock still  _wonderfully_  erect and twitching in the cold air, as they both stared directly at one of the cameras.

Pacifica looked up slowly, and whimpered in frustration as she saw her foot laying directly on the button, marked  _“Primary View Microphone Pickup.”_ However, before she could just die and melt completely into a pile of shame, she heard a quiet and quick conversation as the twins whispered something into each other’s ears.

Then Dipper addressed the camera with a broad grin that Mabel was sharing. “So, there’s still an hour or so before the exchange, Paxy. We’ve got room for one more down here if you’re interested.”

He hadn’t even finished the sentence before Pacifica was out of the room, pausing for a moment to pull her dress back up and try to slightly-reshevel her hair, pulling off her heels, and running down the halls of the manor.


	9. High Five

**Summary for the Chapter:**

> Based on this prompt: "Dipper fisting mabel to a roaring orgasm. After that he plunges into her ass and rides her hard."

Dipper seriously, seriously regretted making those coupons.

Mabel had made him an identical coupon book, like they had the last few birthdays they’d had; It made for a fun little sexy gift at no cost, and Dipper had been excitedly waiting to use his coupon for weeks, the little beglittered scrap of paper reading in magic marker  _“Sexy butt funtimes!”_

However, he’d not been aware that Mabel had been saving one of his coupons, labeled in clean, straight-ruled pen _“The bearer of this coupon is entitled to one (1) evening of pleasurable sex and/or foreplay using the assistance of magic or extraterrestrial technology.”_

 

The biggest thing on his mind had been getting back at Mabel for her last coupon use, which meant she had gotten to pull out her oversized black “Mabelinator” dildo to use on him. While it had been fun at the time, Dipper had trouble sitting comfortably for the next two days, and wanted to pay her back in kind.

So, it was with great gusto that when he presented the coupon to Mabel, he grinned and shook his head when she looked encouragingly towards his pants. Confused, she looked to her drawer of sex toys, but again Dipper let out a short little “Nuh-uh,” enjoying her confusion.

Finally, when she looked back to him, he just held up his fist. Her eyes widened in shock, looking from him to the fist to see if he was serious. Dipper kept his face straight, but internally he was trying  not to fall apart laughing. He’d planned on just freaking his twin out, and actually only massaging and stimulating a bit with a few fingers before filling her with his cock, but until he got to that point he intended to mess with her head in revenge.

However, his confusion turned to a mixture of horror and curiosity as Mabel’s shocked expression turned into one of mischievous glee, and she presented him first with her own coupon, and then rummaged around in another drawer before pulling out a dark pink flashlight with a little multicolored crystal taped to the end.

Her shit-eating grin now wide, she winked to her brother, saying “Stick out your hand, brobro.”

He grimaced, holding it out and squeezing his eyes shut. There was the whooshing sound of the crystal’s effect, and an odd feeling of lightness in his arm. The crystal sounded a few more times, and after the third time he cracked open an eye, letting out a laugh of disbelief at the sight.

Mabel was carefully holding one of her dildos up against his now-shrunken arm, apparently sizing it to something familiar, and when she looked up and saw him peeking, she grinned and gave him a thumbs-up, grinning and glancing between his face and his tiny arm.

Dipper sat there glaring at her for a long few seconds, before sighing and giving her a reluctant, miniature thumbs-up as she squealed with delight.

 

A few minutes later, Dipper was thinking this might have been a good idea. It felt weird as hell to be moving around a limb that felt like it was half it’s original length, but Mabel was cooing and pushing back against his lubed-up miniarm, so he kept going. His free, regular-sized arm reached around from where it had been stroking his cock, and began to run  a finger along her lips, making a circle around her clit as she moaned and leaned back on him.

His miniature arm thrusts sped up as Mabel began pushing back harder, and Dipper’s free fingers moved from her clit to running along her lips, before plunging a finger inside of her. There, he moved them to press gently backwards, against where his arm was thrusting forward to meet her.

The sensation did the trick, and Mabel shuddered, hunching her back and shivering as she moaned out “Ohh,  _ooooohhhh_  man oh man oh man yesyesyes _yesmmm.”_

Taking that as the signal, he withdrew his hand from inside of her, grimacing in instinctive dislike at the tiny fist, and then gently squeezing a dollop of lube onto his own shaft, he slid easily into her ass. Mabel let out a whimper, thrusting back against him as she straightened her back to push against his chest. His large arm reached forward, under her arm to tweak and toy with her nipples, and kissed on the nape of her neck as he continued to thrust, pushing deeply against her as she moaned happily.

The big arm moved down, and he started to pull against her hips, trying to force himself deeper into her as she met his thrusts. Mabel had moved her own hands to replace her brothers as they massaged her breasts, but feeling his uneven grip, she reached behind to his hips, nails biting into his skin as she growled and pulled him hard towards and into her.

He could feel her whole body tense, and that sent him over the edge as well. Dipper came, spasming inside of her as Mabel twitched and made little desperate noises, speeding up her own pace as he slowed, and finally peaking herself as she groaned happily, and slid forward to land on her elbows. Dipper’s shaft slipped out, and he slumped next to her on the bed as they both sighed with ogasmic bliss.

Mabel, making an odd coughing noise, looked him straight in the eye. She raised a hand, in a fist, and said evenly “Fistbump?”

Dipper just glared at her as she broke down giggling, and opened up the hand with a pleading “C’mon, maybe a high five instead?”

 

From outside the apartment, there is a little sound like someone clapping once, and then Mabel’s excited  _“YES!”_  and infectious bubbly laughter breaks out.


	10. Halfway Hidden

**Summary for the Chapter:**

> Based on this prompt: "Dipper gets stuck in a hole with his top half sticking out leaving Mabel in the small tunnel underneath. She'd come along to search for mole people to spend time with him and let him know her feelings, but she was having a hard time getting her point across as he was acting particularly dense. Left with just his bottom half available she realizes she may have to get serious and make sure he couldn't misinterpret her actions this time. Afterwords he asks if she was actually that thirsty and apologizes for not bringing water. Mabel is about ready to give up or simply dig a pit in the basement to keep him in. Instead Dipper tricks her into getting stuck and does the same to her, as it turns out he was just teasing her. "

“Mabel, I’m telling you mole people exist, and we’re going to find one and prove it!”

She rolled her eyes as Dipper pumped his fist into the air. Still, even as he geeked out for the third time that morning about their excursion they had planned for the afternoon, she had to smile a little. The sun from the kitchen window of the Shack was framing his form, making him look like a little lithe sun god instead of her dweeby brother. A  _very_  smoothly-muscled sun god, with a little trace of brown hair visible below his navel as his shirt gave her a peek-

_No, bad Mabel. Add that to the Sin List when you get home tonight; You can’t keep having thoughts about him like that._

Still, her Sin List was getting awfully full nowadays. A couple times she’d held Dipper’s hand far longer than she otherwise would, and even once told him “I love you, Dipper,” getting back a quick “Love you too, sis!” before he went back to the notebook sketch he was making.

Normally, her brother’s obliviousness would have been adorable, but right now Mabel was feeling frustrated, and after her set of particularly vivid and enticing dreams involving Dipper and a certain copy machine, she was dead-set on getting her feelings through his thick skull, somehow.

After wolfing down their breakfasts, the twins set out hiking, Dipper leading the way as he followed a crude map he’d sketched out. They passed what looked like a giant stone foot, made their way through an eerily-quiet yellow meadow, and finally reached a fairly nondescript glade as Dipper crowed with triumph.

There, in the middle of a patch of bare rock between two large patches of moss, was a black crevasse, barely more than a foot wide, and leading down through the rent and into the earth.

“I  _knew_  Old Man McGucket was telling the truth when he said where he saw them,” he said excitedly. Waving Mabel over, he was about to put one foot down the hole before his sister stopped him with a hand across his chest.

“Whoa, hold your horses brobro. Might be dangerous  _moooleee-peeeooopleee_ down there” she said, waving her sweatered arms around for emphasis. Still, despite the levity, Mabel’s face became serious as she pulled her grappling hook out of a voluminous pocket, and shimmeyed down the crack.

She had a moment of panic as she felt like she was about to get stuck, but her hips managed to twist and allow her to slide past the narrowing of the stone. She landed with a crunch on what sounded horribly like bones for a moment, but a quick flashlight check later appeared to be just some twigs and pinecones.

Shining the beam down both directions of the tunnel, she could see it was crumbling in multiple spots, dead-ending from a cave-in a ways down. Mabel called up “It’s safe, brobro,” before turning to shine her light down the open end of the tunnel, her mind attempting to play tricks on her and show her movement where the light revealed nothing.

Behind her, she could hear the sounds of Dipper starting to lower himself, and then abruptly he swore, a crunching noise sounding as he slid and caught. There was more swearing, now muffled, and she could faintly hear him call out “Uh, Mabes? I…I think I’m stuck. A little help, please?”

She rolled her eyes, stepping over to grab a leg, when one of the little wicked thoughts crept through her mind at seeing her brother’s helpless dangling waist at her head level.

_Oh, I’m going to need to reserve a few pages on the Sin List for today._

Stepping forward, she ignored her brother’s calls of “Ok, I think I just put my foot on your shoulder-”, and instead she began to unzip his fly and unbutton his pants, her hands shaking and her breath coming in little pants.

Her twin flinched, but then went oddly still. She heard his voice cut off in a yelp, and then an uncertain voice said “Uh…Mabel? Is that you?”

She rolled her eyes.  _Who else, doofus? A ‘mole-person’?_

Freeing his pants, she slid them to dangle around his legs, and swallowing, slowly hooked her fingers at the edge of his boxers and slid those down as well.

She let out a little whimper of fear and excitement, as even in the indirect light of the flashlight on the floor, she could make out his cock, half-erect and dangling just a few inches from her face.

Apparently, her warm breaths must have been having an effect, as it slowly twitched and grew. Mabel licked her lips, gingerly reaching out to grab his shaft, enjoying the unfamiliar feeling of the skin under her fingers. As she gingerly began to stroke him, the cock twitched again and again, each time growing in her hand, each twinge causing a twin feeling between her leg. Unconsciously, Mabel’s hand slid up her shirt, before she ran it down and under the waistline of her skirt and gingerly touched the damp cotton of her panties.

Finally, taking in a deep breath, Mabel leaned forward, and kissed Dipper gingerly on the tip of his cock.

 

The effect was immediate; She could hear a muffled moan from Dipper above, his legs went limp, and his member gave a happy twinge in reply. She could taste a slight stickiness on the end of him, slightly salty but not unbearable. Emboldened by the response, Mabel took the his head into her mouth, running her tongue up the underneath as she felt his hips twinge.

She sucked gently, running her tongue around in a little circle like she’d read about once, and another muffled groan filtered down to her ears.

She released him, letting his moistened tip glisten in the light as she caught her breath. Her hand had slid aside her panties, rubbing herself furiously, and already she felt a little tightening as she came, whimpering and moaning into the tunnel. Her eyes snapped back up, and she engulfed him, humming a happy buzz onto his cock as she inhaled his scent.

Dipper hips began moving as much as was possible in that tight space, and Mabel moved her head to match the rhythm, enjoying the twinges and groans she could feel and hear from her twin. Then, at the edge of her hearing, she heard him whimper her name.

 

_“Mabel…”_

She jerked her head back as he came, his shaft pulsing and hips jerking as her mouth was filled with his cum. She closed her eyes, swallowing and loving the heat of it the entire time. She began sucking, her hand moving away from where it was doing noble duty rubbing against her lips and ducking an occasional finger inside her, and instead cupped Dipper’s balls, her free hand pumping along her shaft as she continued to suck.

She finally released him with a final kiss on the tip, and then replaced his boxers and pants as well as readjusted her own soaked panties. Then, she stepped forward, putting his limp feet braced on top of her shoulders. There was a momentary delay, and then slowly she could feel Dipper put his weight against them, and a faint cheer that abruptly became audible as he freed himself.

Mabel shifted out of the way as Dipper slid down beside her. Her face was flushed, as was his in the glow of her flashlight, and she inches close to him as he opens his mouth to say:

 

“Wow, Mabes, I had no idea you were getting so badly dehydrated that you’d decide to refresh yourself like that.”

She stares at him, dumbfounded as her brother looks genuinely surprised. He rummaged around in the backpack he’d pulled in the tunnel after him, and passes her a water bottle, still grinning.

_That’s it? Seriously? No “I love you Mabel,” or “That was great Mabel,” or even a terrified “AAAH WHY DID YOU SUCK MY COCK MABEL?” Instead, I get Dipper thinking I went all Bear Grylls on him. Fuck, why couldn’t I have gotten a brother with common goddamn sense?_

She shoved past him, pointing her grappling hook out towards a tree branch overhanging the tunnel. The hook shot out, looping around the tree and starting to yank a seething Mabel out of the tunnel before she could cry or yell or explode at her dense-as-a-post brother.

However, Dipper had smiled, lunging forward, and grabbing her leg as she started to ascend, and pulled her leg to one side, twisting her hips to be perpendicular to the oval tunnel opening.

 

With a  _whoof_ of escaped air and grunt of frustration, Mabel wedged into the same hole Dipper had just escaped from. She was livid, and when he called her name softly, she crossed her arms and huffed.

“Mabel, I just wanted to say…I love you too.”

Her arms uncrossed, her stomach getting little butterflies as he said it, a wide grin breaking across her face. Then she squeaked in surprise as she felt her panties being grabbed at the front and back, and slid off of her legs.

“I also wanted to show you my thanks for _refreshing_  yourself earlier,” he continued, and she could just imagine the smug look on his face.

A moment later, she was imagining a lot of other wonderful Dipper-related things as his finger ran along her lips, tracing her wetness as she shuddered, her hands grasping around at anything nearby.

She couldn’t help but notice that it looked like a set of hands had done exactly that to a clump of grass, and she echoed her brother’s motions by grabbing it as she felt the tip of his tongue gentle lick along her lips.

Her legs now dangled on his shoulders, and his hands were running along them, cupping against her ass, teasing fingers along her slit before a finger gently explored her, slowly taking its time as Dipper teased and discovered her. She hummed with pleasure, biting her lip as he sucked her clit for a moment, before releasing it and kissing in a little circle on her mound and around it.

Then she felt her legs tense, accidentally grabbing Dipper’s head like a vice when he thrust his tongue into her, trailing it up her lips to repeatedly flick at her little nub. She cried out a few times, the sound echoing against the quiet trees around them, and could feel her whole body shudder, shaking and tensing in time with Dipper’s flicks.

Finally, the white light faded, and she could feel Dipper hands at her hips again, this time helping to pull and turn her, and after a second she was free, quickly releasing the grappling cable to land on solid ground.

Taking a moment to catch her breath, she could hear her brother chuckling in the narrow runnel, and grinning, she shoved a hand down into the gap, grabbing Dipper’s arm and helping pull him out as he scrambled out as best as he could.

Sitting on a fallen log, Dipper pulled Mabel close, the side of his hip bumping against hers, and he pulled her in for a kiss. She hummed as she could taste herself on him still, and after a moment, he broke the kiss, smiling at her.

“Care to go  _spelunking_  tonight, Mabes?”

She grinned, and by way of response kissed him deeply again. They got up, holding hands and laughing like they were twelve again as they ran back towards the distant Shack. Behind them, after their voices had faded, the glade and its hidden tunnel remained silent.


	11. Pseudo-Paxy

**Summary for the Chapter:**

> Based on this prompt: "Oh whut about, Mabel maybe tries to spice things up by dressing like Pacifica. Blonde hair, fancy outfit and the like. just to get a rise out of him. Dip is freaked out and turned on. hijinks ensue."

Mabel had been acting mysterious all evening, so when she insisted that Dipper relax and “Await my arrival,” he’d been bursting with anticipation.

_Is it new lingerie? Maybe she finally got some new fuzzy handcuffs, since she lost the keys to the old ones? Ooh, or maybe she got some new flavors of that edible body paint she loves…_

He heard the bedroom door creak open, but as he turned to look, she said quietly “Close your eyes, Dip.”

He obliged, hearing a rustling noise of fabric dragging against the floor. His brow furrowed in confusion; Mabel preferred shorter dresses, and Dipper couldn’t remember if she had anything that went below her knee length-wise. Besides, he normally preferred the shorter ones, for reasons in addition to the ability to slide a hand up a thigh without much difficulty if they were getting frisky.

He followed her movement, eyes still closed, until his sister stood before their apartment’s couch. Her breathing was light, fast with arousal. With a slightly nervous voice, she murmured “You can open them now.”

Dipper looked, and he let out a muted involuntary noise of alarm. Standing before him was Pacifica Northwest, one hand on her hip with her head cocked as she watched his reaction.

His brain fought a vicious battle of opinion with his eyes as Mabel stood before him looking for all the world like the Northwest heir’s body double. Still, he could see her brown eyes instead of Pacifica’s blue, and a loop of curly brown hair was hanging from under the long, straight, platinum-blonde wig.

Plus, while the contouring had made for a striking resemblance, Mabel hadn’t “Maxed-Out” the makeup impersonation; The last time she’d Maxed-Out a disguise, it had been on poor Soos, and his appearance of Grunkle Ford had Grunkle Stan doubting his sanity as Soos started talking about the Earth really being flat like Dipper had prompted him.

Then Grunkle Ford actually had come in the room, seen his doppleganger, and in the ensuing aftermath, as they helped put out the smaller fires they made an unspoken agreement to not go all the way in the makeup department after that.

Still, the resemblance was enough that Dipper could feel his erection twitching and growing in his jeans as he watched her stand there, the slim ocean-blue and floor-length cocktail dress devoid of the normal plethora of sparkles and puffy stickers that seemed to infect most of Mabel’s clothing. Evidently Mabel noticed his physical reaction as well, because the faux-Pacifica in front of him pointed, and in a lightly-mocking triumphant tone shouted “A-HA! I knew you had a thing for Paxy!”

Dipper blushed, but rolled his eyes. “What? It’s not like you don’t either.”

Mabel looked away from him, running her hand to brush back nonexistent brown bangs instinctively as she turned away from him and distractedly muttered “No I don’t. Also, shuddup.”

Her brother grinned, getting to his feet. He took a step, coming sharply up behind his sister as his hand darted up the slit in her dress, resting on her mound. She let out a little gasp of surprise and excitement, as Dipper muttered “I remember your expression when Pacifica gave you that kiss after you saved her from that jaguar demon a few years back. You remember that kiss, don’t you sis?”

He could feel her twitch under his hand, letting out a huff of breath as she bit her lip and moaned out “M-hm”

He leaned close, his hand gently beginning to move along her mound and her inner thighs as he said quietly in her ear “I also saw you two in the library, at her Summerween party this year.”

Mabel’s eyes flew open in shock, but then fluttered half-closed as she melted; Dipper had reminded her of that evening, when Pacifica had come to her, whispered little things to her, and in the privacy of the library, had kissed her lips, her neck, her throat, her chest exactly as Dipper was doing now.

 _So much for privacy, I guess_ , she thought, vaguely regretting making out so obviously in a house filled with hidden security cameras, but before she could let herself get too carried away in happy memories, she turned, kissing Dipper had and passionately on the mouth, before grabbing his shirt by the lapels and leading him over to one of their wooden dining room chairs. She sat him down in one, before straddling his lap and beginning to grind against him.

Dipper leaned back, groaning happily, and Mabel pulled the sodden light-purple lacy thong aside, keeping the garter belt in place as she ground her exposed lips against Dipper’s denim-clad peak. She let out a little moan, reaching behind her brother with one arm to pull her grinding closer to him, while her other hand had interlaced with Dippers before leading it along the top of her dress. She whimpered with ecstasy as he began to rub her breasts, and rose his hips up to meet with her rolling grinds.

Finally, she let upstanding for a moment while still fingering herself, as she helped Dipper get his interfering pants off in record time. Now exposed, Mabel sat back down in his lap, letting out a squeak of surprise and satisfaction as she felt his cock rubbing and bumping her clit. Finally, she couldn’t take the teasing any longer, and lifting herself up slightly, Mabel took Dipper’s shaft inside of her. She sighed, licking her lips and leaning forward to kiss Dipper.

He let out a happy noise, but giggled when looking up at her.

Confused, Mabel looked around, until she realized that a lot of the brown locks of her natural hair had leaked out from under the wig. Giggling, she tossed it into a corner of the room, and leaned in to kiss him again as her hips rocked against him gently.

Between the dress, her appearance, and Dipper’s memories of Pacifica’s affections towards the twins, both individually and together, Dipper could feel himself starting to surge. He gasped out a brief _“I’m s-sorry Mabes,”_  before he came. In response, Mabel pulled her legs around Dipper and the chair, pulling him as far into her as she could manage as he filled her, leaking around the edges as she wriggled happily on her brother.

Mabel leaned forward, kissing Dipper long and hard on the mouth, and then pulling off of his twitching cock to lift her dress aside. Dipper cocked his head, but felt his eye smash shut as his cock twinged when Mabel said innocently “Oh, look at that Dipper; You made a mess, and now I’m dripping everywhere.”

She giggled when he moaned, a final little drop of sperm forming and dripping from where  his cock had been. Mabel scooped it off with a fingertip, sucking it long and sensuously before reaching down to give Dipper’s shaft another pump.

Dipper ducked down, scooping his sister up to give her a kiss on the lips.

"Hey Mabes, you know that holiday party she’s throwing next month?”

Mabel nodded, snuggling up to him as she shook out her brown curls.

“I know about a great hiding spot behind a painting we could… _smooch._..in,” he said, grinning ear to ear.


	12. Trade Ya

**Summary for the Chapter:**

> Based on this prompt: "Turns out Dipper has a thing for skirts. WEARING skirts."

All afternoon, Mabel had been intrigued. Dipper had been gushing over a black faux-leather skirt when they’d been bumming about the mall that afternoon, but when she’d finally given in and modeled it for him in the dressing room, she could see that for a fleeting second before he put on an air of disappointment that it “Wasn’t what he had hoped,” his eyes had sparkled for a movement with undisguised lust and anticipation.

Which made it all the more curious when she’d noticed, as Dipper came out of the store to catch up with her, that partially hidden under a shoebox in the bag was the edge of that same skirt.

 _Oh, brobro_ , she thought, grinning as she watched Dipper tug her into a bookstore,  _You can’t possibly hope to try and outwit the Alpha Twin, and hide how much you’d like to see me in that skirt._

Still, she was certainly loving the idea of surprising Dipper with wearing it tonight. Grunkle Stan was out at poker night again, and Mabel had a particular little red crushed velvet top she thought would match well with the kneehigh boots she had managed to smuggle in past both her Grunkle and her brother.

That night, shortly before their Grunkle left, Dipper had excused himself to go to the bathroom. Mabel smirked internally; Given how distracted and distant he’d been all day, she guessed he was probably going to “relieve some pressure” up in the bathroom. She excused herself shortly after him, figuring she’d probably have enough time to go up and change into the skirt, velvet top, and boots in time to greet Dipper.

As she ran up the stairs, her Grunkle grunted something about not destroying the Shack while he was gone, and the door slammed. Mabel reached the attic, but was confused; The bathroom door was open, the room dark, but the attic was closed and the light was on inside.

Gingerly, she tiptoed to the door, listening intently, but could only make out the sounds of bare footsteps. She gave the door a trio of little knocks, saying “Dipper?” and could hear him gasp, and a scrambling noise. She opened the door, stepping inside, as Dipper yanked her pink bedspread, holding it up to cover himself.

Worried that he was hurt, Mabel started to take a step towards him when he said  _“Don’t!”_  in a pained and fearful voice. She stopped, biting her lip with anxiousness, and Dipper’s eyes locked on the cracked-open door behind her.

“I-is Grunkle Stan gone?” he asked in a timid voice that made Mabel feel three feet tall for barging in on him like that. She shook her head, but closed it behind her anyways with a  _click._

Frowning with concern, she said “Dipper, are you all right? Did you get hurt or something? Do you need me to-”

He shook his head violently, refusing to meet her gaze, and in that same incredibly vulnerable voice he said “No. No, just…Please leave me alone, Mabes. Please.”

She sniffed, feeling a knot at the back of her throat, but nodded, her mind whirling with what he might be hiding from her, but also shame for upsetting him like this. She spun, arms held tightly at her sides, and walked robotically towards the attic door. Her hand had barely reached the metal knob, when she heard a slight sound of motion behind her, and Dipper said hesitantly “Actually, Mabel, don’t go. I-I need to show you something.”

She turned, smiling at him and blinking back her tears of shame and the brand-new surge of relief. Still, she wasn’t expecting the how scared he sounded as he said “If…If you want to go afterwards, though, I-I understand.”

 

Carefully, eyes clenched shut, Dipper held out the edge of the bedsheet, and let it drop. The pink cotton pooled to the floor, revealing Dipper, nude except for the black faux-leather skirt.

 

Mabel stared, and a little part of the back of her mind said  _Welp, I guess I can’t really surprise him with that outfit tonight._

Another part of her couldn’t help but notice that the front of the slightly-pleated skirt had a slight bulge in front, from where Dipper had apparently been sporting an erection until she must have ruined his mood.

Her twin squinted open one eye, shoulder held stiff like he was expecting her to punch him or scream at him, but Mabel just gave him a solemn nod. “You’re rocking that skirt better than I probably could, Dip.”

He relaxed, but tilted his head as he stared at her. “You…you’re not mad at me? For doing something weird like _this?”_

Mabel snickered, smiling at Dipper as she rolled her eyes theatrically. “Dipper, we spent summers in the past fighting zombies and monsters.” She took a few steps towards him, grabbing his hands and giving them a little squeeze in her own as she said in a gentle voice “And then a few amazing months back, we finally figured out that _‘Doy! We love each other,’_ and have had to hide that from literally _everybody_  else.”

He giggled with her at that, and she winked as she said “So Dip Dot, compared to everything else we’ve encountered, _this,”_  she said, waving generally at his skirt-clad lower half,”Is not even budging the needle on the Weird-O-Meter.”

He nodded, slowly, but then looked up with some lingering worry as he said hesitantly “I…I, um, borrowed some of your skirts before, before I got this; Are…Is that ok, or…” He let it hang in the air, but Mabel just let out a dismissive  _“Pshaw!”_ as she gestured to her piles of clean and dirty clothes.

“Brobro, do you have any idea how many of your shirts I borrow?” He looked at her for a long moment before shrugging, and she giggled and answered her own question with “At the moment, more than you by a looong shot.”

Her brother grinned, and then let out a little happy gasp as Mabel gently ran her hand down, to feel across his hardness through the material of the skirt. His ‘Little Dipper’ responded immediately, his shaft stiffening and poking out harder and faster than Mabel could ever remember it going before.

She leaned in, kissing her twin’s neck as he let out a little soft moan, and in a sultry voice she said “In any case, I see you really quite  _enjoy_  wearing my clothes, Dip.” She nibbled his neck as her hand continued to stroke him, the head threatening to peek out from the edge of the skirt as she ran a trail of kisses and gently tickles of her tongue up the nape of his neck, to his jawbone, and then onto his lips.

Breaking the light kiss, she kissed him on the nose and said “Speaking of clothes, close your eyes. I’ve got something to show you too.”

She skipped over to her closet, and Dipper stood in the middle of the room. She watched him as she got everything ready, gasping a little herself as Dip apparently couldn’t wait, his hand reaching down under the waistband of the skirt to grab his cock and pump it lazily. She willed herself to get ready faster, and just a few seconds later the last zipper was zipped and last buckle strapped. She cleared her throat, and said “Ok, Dip. Open your eyes.”

 

This time it was her turn to scuff her foot awkwardly at the floor, as Dipper let out an appreciative whistle. “Originally, I was going to surprise you that I knew you bought the skirt after all, by wearing it along with these,” she said, one hand tugging the bottom of the crushed velvet top while the other brushed against her leg, above the top of the long, heeled boot. between the boot top and bottom of the velvet, she was nude, and thankful again that the attic was always so much warmer and cozier than the rest of the house.

She smiled, winking at him as she continued. “But you made that surprise a bit difficult now, so I figured I could improvise.”

She strode over to Dipper, and kissed again on his bare neck, one hand reaching down to replace his own on his throbbing cock as her other hand gently ran its nails along his chest, as she pushed him towards her bed.

He responded eagerly, his tongue exploring her mouth as one hand ran along her exposed mound, and the other followed the crushed velvet along her back as he pulled her towards him in the kiss.

He reached the bed first, feeling himself bump against it, and on a whim he clambered up onto it. Mabel eyed him with lust for a long moment, loving how the fabric of the skirt attempted and utterly failed in hiding his arousal, and with a growl she followed him up, almost tackling him as she ran nibbles and bites along his collarbone and down his chest.

They both rolled onto their sides on the bed, and Mabel turned and rubbed her ass against Dipper, whimpering as she felt his shaft twitch under her, separated by the thin clothing. Making up her mind, she got up onto her hands and knees, spreading her legs apart and thrusting her uncovered butt towards her brother.

Dipper let out a happy groan, and got up behind her. Slowly, teasingly, he ran a finger along her slit, spreading her and brushing against Mabel with the lightest of touches. She let out a frustrated groan, leaning her chest down farther to poke her ass more skywards, and scooted back towards her twin insistently.

He giggled, and Mabel could feel the edge of the skirt being lifted up to rest on her ass, as he grabbed his cock and ran the head back and forth along her slit, maddeningly replacing his finger but doing the same taunting motions.

She let out another whimper, but before she could scoot back and take matters into her own hand, Dipper slowly leaned his hips forward, his shaft slipping inside her.

Mabel groaned, loudly enough that she bit at the covers and blanket to stop herself despite knowing full well that their Grunkle would be gone for multiple hours at the minimum. Lifting her hands up from where they’d been supporting her limp form, Mabel grabbed her brother’s skirt-covered ass, pulling him deeper into her as he let out a breathless whimper of his own at her touch.

His hands moved from her hips, at first reaching up to her shirt to grab and tease her breasts through the fabric, before his hands migrated south, and gripped around the top of her boots along the midline of her thigh. He ran his hands along them for a second, before beginning to use them to pull against her as well, his thrusts slamming into her and causing her heart to skip a beat with each internal shudder of pleasure he caused.

She had come already a few small ones interspersed with her brother’s thrusting and her own occasional pleasuring, but the swell of a large orgasm began to nudge at her, and she leaned all the way up, slamming almost vertically down on to Dipper’s cock, as his hands moved back up to her chest, lifting the shirt up to wrap his arms around her and help stabilize her as her movements became erratic, hyperventilating with a series of little gasps interspersed with brief wordless moans.

As the peak hit, and Mabel’s world went a pleasant fuzzy whitish-pink, one thought floated to the top of her mind.

_Oh, we are definitely “sharing” outfits in the future. Oh yessiree, ohh, mmhmmm yiss Dip right there ohgod yes yes mmm mmph yes ah-AH-_

Letting out a scream of pleasure, Mabel tightened around her skirt-clad brother as she came.


	13. I've Seen Enough

**Summary for the Chapter:**

> Based on this prompt: "Tentacles pls"

“Beatrice, _please..”_

Dipper again begged the old Hand Witch, as she fussed about, cleaning up some shed fingernails near one corner of the cave. “Oh, I don’t know, I don’t know,” she said, her voice unsure as she kept glancing over at the young Pines boy.

“My cousin is an  _odd_ bird, make no mistake, and you still want to get an enchantment from her?”

He averted his eyes, shrugging and scuffing the gritty floor with his boot as he said in a hesitant voice “Actually, I, um, I read up on your cousin’s specialty, and, uh, that’s  _why_  I contacted you, to ask her about it.”

The Hand Witch stopped, Beatrice narrowing her eyes in shock and sudden suspicion. Waggling a finger at him, echoed by the fingers perched on her shoulders and the shelves of her wall, she said “Now just a moment there, young man; Why would you  _want_  an enchantment like-like  _that?”_

In an equally timid voice as before, Dipper muttered “It’s a gift. For a-for a friend.”

She stared for a long moment, before letting out a cackling laugh as a rain of disembodied hands rained from the ceiling, clapping Dipper on the back good-naturedly, if a bit repetitively.

 _“Well,_  that changes everything! Give me a few days to get word back from her, and I think I can call in that favor she owes me for it, as my thanks to you for helping me meet Jeremy!”

As if on cue, her boyfriend’s head peeked around the entrance to the cave, and gave Dipper a wave he returned. Beatrice ran over to hug him, a swarm of hands following her, and coughing awkwardly at the sounds coming from the seething mass of bodies and hands, Dipper excused himself from the cave.

Now all he had to do was wait.

 

 

Dipper was buzzing with excitement when he came back from the mall that Friday, and on the kitchen table of the Shack was a black burlap bag square in the middle of it. There was a tag, bearing just his name in exquisite penmanship, and Grunkle Stan was sitting there, a peeved look on his face and his hands crossed on his chest.

“Uh, hey Grunkle Stan. Thanks for grabbing the package for me-” He cut off as Stan just “hmphed,” glowering into a corner.

Then Dipper abruptly saw what was wrong, and said “Uh, did-did everything go all right with the Hand Witch?” as he tried to cut back a smile with only middling success.

His Grunkle shot him a dirty look, rolling his eyes and further squeezing his hands across his chest. The effect was slightly ruined as they both pivoted at a 90 degree angle to wave gently at Dipper in unison.

“What do you think?”

Dipper choked off a snicker, but shrugged when Stan grumbled, grabbing his free hands as best as he could with the glowing-violet stumps, and went off to his study to sulk. Dipper approached the table, gently pulling the burlap open to peek at the contents.

It was a large, head-sized mason jar of blue liquid, with strands of what looked like clumped spaghetti strands floating to the surface. The smell seemed like a locker room floor, and he coughed involuntarily. Inside was another tag, this one written on printer paper instead of a scrap of cardboard, but the words looking like they’d been written by a stunned toddler instead of a calligrapher.

_“To use:_

_Apply to areas you want to affect, and take one sip for every 15 minutes you want the effect to last. If the effect lasts longer than four hours, you probably drank too much. Do not induce vomiting.”_

Dipper grabbed the bag, and taking a quick peek out the door of the Shack, ran off towards a secluded area of the woods where he could be undisturbed. He went until he was sure the Shack was out of earshot, and carefully set the sack down next to a clump of ferns. Unscrewing the top, he dipped a small travel cup from his pocket into the jar, dabbed two of his fingers into the sticky, viscous liquid, and putting the cup to his lips, took a tiny sip.

Dipper’s ensuing scream echoed throughout the woods.

 

 

That night, Mabel returned from the mall, giggly but still interested in seeing what her favorite brother had been up to all day. However, Dipper was evasive, just saying “Eh, minding the gift shop,” despite their Grunkle specifically giving them the day off. Even lifting up her sweater and giving Dipper her patented “Double Sweater Puppy Flash” elicited little more than a drained laugh, and an apologetic “Sorry, Mabes, but I’m not feeling up for fun tonight. Maybe tomorrow instead?”

She huffed, but nodded, and Dipper rolled over in bed to face the wall. Mabel watched him, biting her lip for a moment as her afternoon of looking forward to sexytimes with her brother was abruptly dashed. She grabbed her sequined laptop, flipping open the pink lid while plugging in a pair of kitten-paw earbuds, shooting nervous glances at her brother the whole time to make sure he really was asleep.

Her hands twitching a bit with anticipation, she opened a web browser, and began typing in the first few letters. It autofilled in with the rest of the address, and Mabel blushed a little as the little number _“52 Visits”_  appeared next to the address.

 _Time to make it 53,_  she said silently to herself, and she hit _Enter._  A video screen popped up, and in her earbuds a familiar background song started; As always, it started exactly where she had advanced the video to start from the first few views, her preferences now saved to avoid her a lot of boring exposition she couldn’t understand.

Instead, there was just the sound of a girl whimpering, and a male voice starting to say  _“Watashi wa anata no naibu-”_

Quietly, so as not to wake her brother, Mabel let out a gasp in unison with the girl in the animation, as her hand rubbed through her panties that were damp with foiled anticipation. She bit her lip, harder this time as her legs spasmed together, and the familiar sounds of the video continued.

Meanwhile, Dipper was fully awake, and a brief peek had revealed his transfixed sister doing exactly what he’d caught glimpses of her doing on evenings before. He rubbed his sore backside, but grinned in anticipation as he looked back towards the wall.

 

 

The next day passed by almost too quickly, as the twins worked in the gift shop, selling tchotchkes to gawking tourists. It wasn’t a glorious or high-paying job, but they had both elected to attend community college, and the wages their Grunkle paid were enough for them to make the trip out to visit friends and the Shack for the summer.

Mabel had attended the register while DIpper stocked, and a couple times he stole kisses or grabbed her butt when tourists weren’t around. They almost got caught when one little kid barged in asking for the restroom, but as he fled the two just burst into giggles as she laid a peck on his forehead and birthmark.

They had just finished dinner when Grunkle Stan left for his weekly bowling game that evening, spouting off about how “Glad he was to have them back,” whatever “them” referred to. Mabel didn’t get a chance to pry, as he was already out the door just a minute later, and Dipper got up after the door slammed shut.

He strode around to Mabel, who was now eying him with amusement, but made a little half-nervous, half-aroused giggle as he planted a kiss on the nape of her neck.

“I’ve got a special surprise for you Mabes, for tonight. Would you be able to wait outside on the porch until I text you that it’s ready?”

Mabel grinned, nodding and bounding out the door. She had suspected that Dipper had something up his sleeve; He had done something similar last year when he’d presented her with the tub containing one of the only batches of  _Smile Zip!_  ever made. Apparently the caffeinated Smile Dip was supplied by a friend of Grunkle Stan’s, and remembering the taste of the technically-fruity powder made her heart begin to beat arythmically with the memory.

 

She squeaked with excitement when her phone buzzed quite a bit later, not bothering to check it and instead bursting into the living room. She felt her heart sink a little as no sugary contraband was in sight, but a different kind of excitement made a little rumble inside of her when she saw the clothes Dipper had laid out on the couch.

Placed out, he had put a navy-blue skirt, a little tight white blouse with short sleeves, some long white stockings, a pair of Mabel’s favorite black heels, and a matching navy bow for her hair. She grinned, shaking her head a little at Dipper’s apparent new style kink; She had obliged him with everything from a Slave Leia outfit to, for some reason, seven different sets of identical lingerie in a rainbow of colors, and while this set was new, it certainly wasn’t something she was taken aback by.

 _Still,_  she thought, feeling a little thrill of excitement, _He managed to pick something that looks enough like that girl in the video that we can always let our imagination wander a little tonight, right?_

She felt a swell of heat build between her legs at the idea, and quickly changed into the outfit. Under the skirt was a post-it note, that said “When you’re changed, meet me in the attic.” She giggled, ascending the stairs as quickly as the heels allowed, wishing a little that Dipper was behind her to appreciate how her lack of panties and the ridiculously-short skirt interacted with how her legs moved going up the stairs.

The attic door was cracked open, and she nudged it open with her hand, smiling as she stepped into the room and shut the door behind her. Her gaze immediately went to Dipper’s hair; He had some kind of comb-in dye in it, which resulted in a uneven but mostly-uniform black coloration. Then she surveyed his outfit: A brown suit and pants, white dress jacket left partially unbuttoned, and-

_Glasses? Dipper doesn’t wear-_

She stopped, a lump of horrified realization getting into a knife-fight with her surge of dawning excitement as she recognized his outfit. _I don’t look “enough like” her, I look exactly like her. Oh man, and Dip looks exactly like-_

Her excitement won out, and she took a few steps forward as he grinned and beckoned her over with a finger. She stopped, doing a little twirl when she was next to him, and in a little embarrassed voice said “So, uh, I take it you’ve seen my browser history?”

Dipper just smiled, leaning in to kiss her and muttering  _“Watashi wa anata no naibu ga watashi no tame no yorokobi de senkai kanjitaidesu.”_

Mabel let out an involuntary gasp of excitement, feeling like someone just poured gasoline on her internal flame of passion as it roared into a hungry inferno, when several things happened in quick succession:

 

Dippers fingers began to lengthen, starting to wrap Mabel in an unnatural and fleshy grip as he scooped her off of her feet.

Mabel squealed in alarm, starting to thrash at the sudden ambush.

Dipper stopped, loosening his grip and leaning Mabel back upright while concern suddenly peppered his face.

Mabel noticed his worry, and his calmness throughout the initial grabbing, put two and two together, and let out a shuddering happy gasping moan as she realized exactly what Dipper was doing and how close his actions were mirroring that of her memorized video.

Dipper grinned, and scooped her off of her feet again, his fingers lengthening like rope to wrap around his sister.

 

Mabel thrashed, but her squeals were now of excitement, interspersed with her unquenchable giggles, and Dipper gave his best evil-villain chuckle, which devolved into snickering as Mabel laughed at it too. Still, her giggle turned to a moan as the free ends of his unnaturally-lengthened fingers began to rub and explore along the outfit, the tips wrapping around her bra-less breasts before flicking and rubbing against the nipples.

She shifted her hips as well, and there Dipper’s new tentacles had wrapped around her upper thighs, but not brushed against her lips yet. She bucked her hips again towards her twin, making a pleading insistent noise as she looked at him with big doe eyes. Dipper chuckled, and with a little effort, brought his sister around so he could lay kisses against her collarbone as she was suspended in front of him.

The kisses drifted downwards, as two fingers gently tugged her blouse apart, and Dipper laid a single kiss on each of her nipples, giving them a fleeting nibble before pivoting her backwards. Mabel let out a squeal of delight at the teasing and then the flip, and then her breath caught as Dipper gently kissed her on her slit, before a quartet of fingers helped spread her lips, and he gingerly ran his tongue up her.

Mabel just whimpered, letting out a strangled  _“Please_ ” as his tongue reached her clit. He obliged, running his tongue in an orbit around it before laying a brief kiss on it.

She let out a little faint  _“Nooo, Dip,”_  as her tone pouted, but Dipper just turned her around to hover in front of him again.

That’s when he lowered his pants, revealing the engorged and stiff cock. With a careful adjustment, his fingers opened up his sister, and slowly, his cock stretched out to meet it, finally resting at her entrance for a moment before the tip rubbed upwards. Mabel groaned as his cock taunted her, and then she tensed and let out a held breath as he slid into her, pulling her deeper onto his cock as she licked and bit her lip.

She tensed, her legs shuddering as she squealed and came, tightening around and milking Dipper’s cock as she gasped for breaths. He groaned, feeling the sensation of his sister’s orgasm, and he could feel himself starting to tighten as well.

He leaned her forward, whispering urgently “Mabes, I’m gonna come. Did you want it there, or-”

Her eyes flew open, and she opened her mouth wide by way of response. Dip nodded, feeling the sensation slow as the relatively-cold air of the attic brushed against it, before sliding it in towards Mabel’s mouth.

She took it hungrily, sucking it and then working his cock with a free hand once his finger-tentacles released it. He groaned, letting out a brief _“hngh!”_   before he came, and Mabel coughed, spluttering as his cum dripped from her mouth to stain the untouched blouse. Still, she swallowed what she’d caught, and Mabel began licking and cleaning his cock head as it continued to slowly shrink back to its normal size.

In the afterglow, Dipper pulled his sister close, and she giggled and demanded to see the magical elixir when he described the sack and jar it contained. Mabel had then carefully taken the sample he’d withdrawn to show her, and with a careful paintbrush had drawn two equal stripes on his cock, separated by a thin band of unpainted flesh.

“Ok Dip, give it a go!”

He closed his eyes, concentrating, and then suddenly two halves of his cock began to grow from the painted regions. He gasped, grinning as he looked at Mabel; His sister looked like she’d won the lottery, and that lottery was of all of her sexual fantasies in a single heap.

As she rubbed herself and lifted up the skirt, ready to lower herself onto her brother’s now-twin shafts, Mabel leaned forward, giving her brother a kiss as he filled her again.


End file.
